It is well known in acoustics that the dispersion pattern of a sound source is related to the size of the radiating element. This causes conventional electro-acoustic transducers, or loudspeakers, to have an off-axis response that degrades with increasing frequency. This has long been regarded as a basic problem in loudspeaker design and over the years several different solutions have been proposed. These include the use of multiple transducers, horns and waveguides, electrostatic elements, and acoustic reflectors of varying shapes. Many of these solutions have undesirable side effects such as the introduction of frequency response anomalies and complicated fabrication techniques. Furthermore, these systems as well as conventional loudspeakers can act in unpredictable ways in typical listening environments due to the lack of consideration usually given to the human auditory perceptual system.
The recreation of sound via loudspeakers can be enhanced by controlling the direction, amplitude and spectral content of the sound arriving at the listener's ears via the loudspeaker/listening environment combination. It is the purpose of this invention to address all these issues in a single device which is simple to manufacture. When properly mated to a suitable conventional transducer, the invention causes sound to be transferred to the listening environment with a nearly frequency-invariant horizontal dispersion pattern. This affords a greater number of listeners with timbrally accurate sound with a greater sense of envelopment due to greatly enhanced lateral room reflections. Furthermore, floor and ceiling reflections are reduced causing increased stereophonic phantom image stability. A number of the invention's features can be modified to suit the designer's particular needs when incorporating the invention into a complete loudspeaker system.